The EU called Friday for deadlocked Brexit talks to be intensified, with German Chancellor Angela Merkel saying the next few days are essential for a breakthrough.
EU bosses spoke as the final round of scheduled trade talks wrapped up in Brussels with just two weeks before an October 15 EU summit that is largely seen as the deadline for a deal.
"It will become clear in the next few days whether we are making progress or not," German Chancellor Angela Merkel said after a EU summit in Brussels.
"As long as the negotiations are going on, I am optimistic. I cannot announce a breakthrough as a matter of course," she added.
European Commission chief Ursula von der Leyen will hold video talks with Britain's Prime Minister Boris Johnson on Saturday to take stock of progress, and to determine her counterpart's willingness to find an accord.
"Where there is a will, there is a way, so I think we should intensify the negotiations, because it's worth working hard on it," von der Leyen told reporters.
"We're running out of time," she added, noting that there were less than 100 days until the end of a post Brexit transition period that ends on December 31.
- 'Not at the tunnel' -
Von der Leyen, whose commission is running the trade talks for the EU, stressed that both sides had made progress on "many, many different fields."
"But, of course, the most difficult ones are still completely open," she said.
EU and UK negotiators Michel Barnier and David Frost were meeting in Brussels on Friday to close out the round of negotiations -- but no major breakthrough was expected.
Britain and Europe still disagree on how to assign fishing rights in UK waters and how to maintain a so-called level playing field in business and state subsidy regulations.
Diplomats say that the British side has been pushing for the negotiations to head into a "tunnel" -- diplomatic jargon for a closed door, secretive dash to the finish line, allowing negotiators to make concessions without public pressure.
But European officials say the time is not right, as they are yet to be convinced that Johnson can be trusted to budge. "We're not there yet, we're not coming in to land, we're not at the tunnel," one said.
The von der Leyen and Johnson call also follows the launch of a legal proceeding by Brussels in response to the British government's attempt to overturn parts of the Brexit withdrawal agreement.
On Tuesday, British MPs backed a bill to regulate the UK's internal market from January 1, when Britain completes its post-Brexit transition period and leaves the EU single market and customs union.
- 'This is bitter' -
If Britain does not back down, the infringement procedure could go all the way to the European Court of Justice, which would be able to impose large fines.
Johnson has pushed on with the legislation -- despite concerns in his own party and a warning from Washington that it puts Irish peace at risk.
Asked her reaction to the law, Merkel said: "This is bitter, I must say."
The row over the bill has not scuppered the trade talks, but increased doubts among the Europeans that Johnson is pursuing the deal.
The trade deal is intended to give Britain wide access to the European market, quell EU worries that post-Brexit UK will undermine bloc standards, and set limits on state aid.
Failure to reach a deal would put EU and UK relations on minimum standards set by the World Trade Organization and cause a severe shock to their interdependent economies.
Negotiators are stuck on several lingering issues including rules for paying state subsidies to private companies and distribution of fishing rights.